The trial of a Hong Kong journalist accused of spying in China has opened in Beijing. Reporters are calling for a fair trial for Ching Cheong.

Singapore daily Straits Times correspondent Ching Cheong was brought to trial at the Beijing Number Two Intermediate People's Court.

Ching was arrested in southern China in April 2005 for espionage. His wife says Ching was working on a manuscript about the former Chinese Communist Party leader Zhao Ziyang when he was detained.

Zhao was ousted in 1989 after he showed support for pro-democracy protesters in Beijing's Tiananmen Square. The reformist leader spent the rest of his life under house arrest.

Ching is the first Hong Kong journalist to be arrested in China since the former British colony returned to Chinese sovereignty in 1997.

Ching's colleagues in Hong Kong are worried that he would not get a "fair and just" trial in Chinese courts.

"We are so worried Mr. Ching's hearing would not be fair," said Serenade Woo, the chairwoman of the Hong Kong Journalists Association. "The case will be conducted in camera [secret] and Mr. Ching's relatives cannot attend the case. We actually do not know what is happening inside the court room."

The association held a candlelight vigil to show support for Ching and his family.

Woo says Ching's case could hurt the ability of Hong Kong journalists to report in the mainland.

"Mr. Ching went to China to carry out his journalist responsibility," she said. "What does that mean for the central government to say that 'we see he is doing some kind of spy activities'? Or what is the exact meaning of the law talking about 'secret'? Because when we look into the law it seems so vague, there is no definite meaning of 'secret.'"

Reporters in Hong Kong enjoy the freedom to publish or broadcast news uncensored, unlike their colleagues in the mainland. Hong Kong's leader Donald Tsang had promised to lobby Beijing for Ching's release.

The international media watchdog Reporters Without Borders says China imprisons more journalists than any other country. New York Times researcher Zhao Yan, accused in 2004 of revealing state secrets, remains in detention awaiting a verdict.

China in recent years has arrested several Chinese academics and reporters on spying charges. Most of them were convicted and imprisoned.

In another case, lawyers for Chen Guangcheng, a Chinese legal activist, say he will go on trial Friday. Chen was arrested in June after exposing alleged abusive enforcement of birth control policies in eastern China.